Earlier this year at the Detroit Auto Show, we heard about Porsche’s hybrid race car that garners energy from a flywheel, and now a consortium called Flybus has put that energy reusing technology into a regular bus. This simple technology takes kinetic energy generated as the vehicle is breaking and winds up a flywheel that feeds energy back into the wheels when acceleration begins again. The flywheel can be wound up to a maximum of 60,000 rounds per minute and can pack some serious emissions-free energy, making both gas powered and electric vehicles more efficient. Another perk? Hybrid-electric buses can be really expensive, but engineers believe this hybrid flywheel system could sell for a fraction of the cost.

The engineers involved in the Flybus consortium come from many different companies and call their invention the Optare Solo Midibus. The companies have banded together to use their expertise to execute a single vision in making buses more efficient — Torotrak has provided the transmission, Ricardo provided the flywheel, Allison provides transmission expertise and Optare is a major UK bus and coach company. The project has been partially funded by the UK’s Technology Strategy Board and will be presented at the Low Carbon Vehicle Event which takes place this week in the UK. Though the idea has been proven feasible the group hasn’t tested the actual fuel savings of their design — that’s the next step in the process.

“The recovery and reuse of kinetic energy during stop-start drive cycles is a priority for bus operators, not just because of the positive impact on emissions but also because it reduces fuel costs and brake wear,” says John Fuller, Product Leader for Kinetic Energy Recovery Systems (KERS) at Torotrak. “Electric hybrid systems are expensive, often doubling the transaction cost of a bus. Initial cost estimates suggest that the Flybus system could be available at a fraction of the cost of an electric hybrid, whilst simulation results indicate fuel savings comfortably in excess of 10%.”

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2 Comments

lazyreaderSeptember 6, 2011 at 4:40 pm

Keep in mind the technology that benefits this bus will in the end be introduced to the mass market, drawn down by the automotive industry for passenger cars. The ability of cheap technology further aiding the fuel performance of existing or new automobiles only serves to render the bus unnecessary. If you can put a flywheel in a car or SUV, you’ll be in better straights than going on a bus. By 2025 the average car will be 20-30 percent more efficient than the average car today and the average light truck will be 15-20 percent more energy efficient than current models. So the energy efficiency of transit is gonna be negated because we keep building transit in places where few use it, were talking people that already have garages and cars, they don’t have to commute to the city either, the idea of the downtown area is a largely obsolete concept. Fortunately we live in cities different in design than past, it renders transit functionally irrelevant except in bigger cities.

lazyreaderSeptember 6, 2011 at 11:14 am

If the buses are less expensive, why did we buy all of those electric hybrid buses. Transit agencies have probably spent billions on thousands of hybrid buses only to be forced to do so again in the future to buy these. Of course they haven’t amortized the costs yet (nor will they now that the buses will most likely be retired earlier). All over the country, transit agencies are purchasing hybrid-electric buses, natural-gas-powered buses, and other alternatives to Diesels, which have a reputation for being dirty. While transit is popularly believed to be environmentally friendly, the truth is that it is not, and this is especially true for buses, which typically use more energy and produce more pollution (at least more of the kinds of pollution that are of greatest concern today, namely CO2, NOx, and particulates) per passenger mile, than autos and even SUVs. Vanpools are actually the most efficient transportation means. Electric buses, for example, cost $1.2 million, which one news story claims is “twice as expensive as a regular bus.” Make that more than four times as expensive: a standard, 40-foot transit bus starts at around $300,000, but the electric buses are only 35-footers, they claim to hold 68 people, that’s only with most of them standing; how comfortable. Never mind the fact the transit agencies across the country have to “hike its fares” and implement system-wide service reductions due to budget problems. But it can still spend more than four times as much as it needs to buying new buses. The buses purchased with federal stimulus grants that should only be spent on capital projects. Hybrid buses can cost up to $500,000,” while natural gas buses are only $20,000 to $50,000 more than the $300,000 cost of Diesel bus. Overall diesel buses today meet strict EPA heavy-duty Diesel emission standards, so this is much less of an issue than it once was. And Diesel buses tend to cost less for transit agencies to own and operate.